martedì 29 giugno 2010

Primary osteosarcoma of the mandible

Findings

There is destruction of the vertical ramus of the mandible on the left side with associated periosteal reaction and osteoid matrix (Figure 2 and Figure 3). Multiple lamellae are seen radiating from the lesion giving it a sunburst appearance. Also there is extension into the soft tissue of the face (Figure 1).

Diagnosis: Primary osteosarcoma of the mandible

Malignant tumors of the mandible can be grouped as odontogenic and non-odontogenic. Examples of non-odontogenic solid malignant tumors include sarcomas, metastases, multiple myeloma, lymphoma/leukemia, and squamous carcinomas. Osteosarcomas of the mandible are rare non-odontogenic tumors and account for 5-13% of all osteosarcomas.

Osteosarcomas of the jaw generally peak during the 3rd or 4th decade, as opposed to osteosarcomas of long bones which peak during adolescence. There is no conclusive gender predilection. It can be secondary to Paget disease, fibrous dysplasia and irradiation to the jaw. Clinically the patients present with painful jaw swelling.

Typical osteosarcomas show matrix mineralization, which may be osteoid or chondroid, with associated bone destruction and soft tissue extension. With large tumor size these signs are identified on a plain radiograph, and CT scan helps in describing the extent of involvement. For cases presenting early CT helps in identifying those missed with conventional radiography. Differentiating osteosarcomas from chondrosarcomas can be troublesome radiologically and sometimes even histopathologically; however chondrsarcomas are even rarer in the head and neck region.

Histologically, this tumor is less aggressive and less frequently high grade as compared to its conventional counterpart in the long bones. The spread of the disease to the cervical lymph nodes is seldom seen.

Osteosarcoma of the jaw should be treated with radical surgery as the primary modality. The single most important factor in curative therapy for osteosarcoma of the jaw is its amenability to radical resection with clear margins. Neoadjuvant chemotherapy is not used as a routine as against osteosarcoma of long bones. There is no general consensus over the role of radiation therapy in management of patients. In one study Delgado, et al. reported that when surgical margins are not free of disease, the use of radiation does not improve the outcome.